Wheels for the Bee

If you have read some of the other pages you will know that I was struggling to launch this thing.
I saw the image at right
and thought I can do that
by myself, ie, fit wheels to my Windrider Bee.

I grabbed some 4mm plywood (just ordinary pine), bought some wire and wheels and had at it. The result is shown below.

The first version of the wheels mounted on the wing. They are held on by 2 cable ties, one that goes through
the motor mount at the back, and the one that holds the battery in as well.
An issue here is that takeoff takes a long run because the wing does not have enough incidence. Basically it gets off when the
nosewheel hits a bump and bounces up! The bolts holding the plywood away from the surface at the back are the problem, since if that area
was flat and the plank could be held flat against the trailing section of the wing it would be at about the correct angle.

Despite that problem, I had a few good flights with it like this. In the lower image you can barely see that there is red tape
on the plank, which is covering some big holes I drilled because the wheel assembly adds significant weight.

To solve the takeoff run issue I cut some balsa blocks to put between
the plank and the wing. The first was 10mm and worked quite well until
it fell out during a flight. I then put in a 12mm block which worked
even better but increased the drag during flight.

The ultimate solution to the angle issue is a new nosewheel that
is longer. As I added angle between the plank and wing I noticed it
needed more and more up trim, and flew a bit more sluggish. The sharp
will notice that this nosewheel is made from 3.2mm wire like the back
legs, whereas the first nosewheel was 2.4mm wire. I found that even a
reasonably slick landing would bend the 2.4mm wire. The new one has a
few turns for spring but it is heavier, so I cut the plank shorter to
keep the CG in the same position. Some would say that if I'd left the
plank long I could then remove some noseweight to rebalance, thus
reducing AUW. I chose not to do that because I want the wing to be
balanced without the wheels mounted so that I can choose to fly without
the wheels. I believe a better solution to the excess weight is to move the
motor further forward and use a long shaft and extra bearing to support the prop at the back.

As at 11/25/2009 this modified nosewheel is unflown so hopefully
I'll remember to come back and report on it. We're having a season of
such high wind at the moment such that no-one flew last weekend, and it is
still blowing.

I am considering some options for the future, one being to mount an
extra servo that can ditch the wheels after takeoff since it does fly
rather nicely without the wheels. Another is to make some sort of
elastic powered launcher, something like a spear gun that can be fired
one handed.

At least now I can fly it with a good assurance of not breaking the
prop, so now I can try some different props that I have, that cannot use
the prop saver.